This study will assess whether a bladder cancer excess exists among rubber workers in Akron, Ohio, and whether the occurrence of bladder cancer is associated with exposure to specific chemicals or jobs within the industry. The study will compare bladder cancer death rates in four cohorts of workers (from the four major rubber companies in Akron), for the period 1964-73. Age-standardized mortality ratios will be calculated, using State and national mortality data as the "standard". Some preliminary mortality calculations have been made, indicating (approximately) a 30% excess mortality from this cause. Proportional mortality analyses may be done of bladder cancer deaths at non-Akron plants. Subsequently a case-control investigation will be performed with the specific work-exposure correlates of bladder cancer. Approximately 800 cases of confirmed bladder cancer have been identified from the four major hospitals in Akron, for the period 1958-74. Within this group, an anticipated 200 rubber workers will be identified (by cross-checking against company employment records). These rubber worker cases will then be individually matched with two rubber worker controls (both on sex, race, birth date, plant; one, additional match on date and duration of employment), and differences will then be sought between case and control work histories.